1. Field of the Invention
This invention relates to an electric connection box in which the connection between a connector tab terminal and a conductor circuit on an insulating plate, as well as the connection between the tab terminal and a wire, is improved.
2. Description of the Related Art
An electric connection box is used for branch connection of automobile wire harnesses or the like to various electric equipments, and serves to provide one centralized branch connection point so as to effect the branch connection of wiring go in a rational and economical manner. With a high-density design of wire harnesses, there have now been developed various types of electric connection boxes designed respectively for various kinds of automobiles and various uses.
In one known electric connection box shown in FIG. 18, many lock claws 1b are formed on a peripheral wall 1a of a lower casing 1, and lock recesses 2b, corresponding respectively to the lock claws 1b, are formed in a peripheral wall 2a of an upper casing 2. Insulating plates 4, each having a conductor circuit formed by bus bars 3 or other, are received in an internal space formed by the two casings 1 and 2, and the upper casing 2 is fitted on the lower casing 1, and the lock claws 1b are engaged respectively in the lock recesses 2b, thereby locking the two casings 1 and 2 to each other.
Hood portions 2d of connector housings 2c are formed integrally with the upper casing 2, and terminal passage portions (not shown) of these connector housing 2c are formed through the upper casing 2 (The lower casing 1 is also provided with such hood portions and terminal passage portions) . When the two casings 1 and 2 are joined together in a closed condition, tab terminals 3a, formed by bending on the bus bars 3, extend into the corresponding hood portions 2d through the corresponding terminal passage portions.
In the above construction, the tab terminals 3a are formed by bending on the bus bars 3, and therefore the position of each tab terminal 3a, formed by bending, is limited, so that the degree of freedom of the circuit design is low. Therefore, it has been proposed to secured separate tab terminals 3a to bus bars 3 by soldering.
In order to achieve a compact, lightweight design of an electric connection box, there has been proposed another construction in which instead of the above bus bars, an FPC (flexible printed circuit member) or a PCB (printed circuit board) is used, and separate tab terminals are soldered to a conductor (copper foil) circuit of the FPC or the PCB.
However, when the tab terminals are soldered to the respective conductor circuits, there is a possibility that cracks are produced in the solder, for example, by a heat cycle developing in an automobile on which the electric connection box is mounted. Therefore, the reliable electrical connection can not be obtained for a long period of time. And besides, in the case of an FPC or a PCB, the soldering is effected by a flow process, and therefore the time and labor, required for the assembling operation and the flow process, increase in connection with the use of the lower and upper casings 1 and 2. In the case where flexible printed circuit members are stacked together, tab terminals, connected to these flexible printed circuit members, have different heights, and therefore a plurality of kinds of tab terminals of different heights are needed, and therefore the parts stock control is cumbersome, and the cost increases.
And besides, in some cases, the electric connection box contains a circuit through which an electric current of a large value flows, and wires (single-conductor wires) are often used in addition to an FPC or a PCB. In this case, the same problem as described above is encountered with the connection to the single-conductor wire.
This invention has been made in order to overcome the above problems of the conventional constructions, and an object of the invention is to provide an electric connection box in which the connection between a connector tab terminal and a conductor circuit on an insulating plate, as well as the connection between the tab terminal and a wire, is so improved that the electrical connection of high reliability can be achieved and that the time and labor, required for an assembling operation, can be reduced.
Another object of the present invention is to provide an electric connection box in which the connection between an inexpensive connector tab terminal and a copper foil of a flexible printed circuit member is so improved that the electrical connection of high reliability can be achieved and that the time and labor, required for an assembling operation, can be reduced.
In order to solve the above problems, according to an aspect of the present invention, there is provided an electric connection box wherein an insulating plate, having a conductor circuit formed thereon, is received in an internal space formed by a lower casing and an upper casing, and a tab terminal is electrically connected to the conductor circuit;
wherein there is provided a terminal holding portion which can be fixed at a predetermined position in opposed relation to the insulating plate, the terminal holding portion having a hole for passing a tab portion of the tab terminal therethrough; and the tab terminal has a tongue-like spring contact portion; and when the terminal holding portion, having the tab terminal passed therethrough and held thereon, is fixed at the predetermined position, the tongue-like spring contact portion of the tab terminal is resiliently contacted with the conductor circuit on the insulating plate.
In the invention, the terminal holding portion, having the tab terminal passed therethrough and held thereon, is fixed at the predetermined position, and merely by doing so, the electrical connection between the conductor circuit and the tab terminal can be achieved through the resilient contact of the tongue-like spring contact portion with the conductor circuit.
In one specific form of electric connection box of the invention, a hood portion of a connector housing and the terminal holding portion are formed integrally with one or both of the lower and upper casings, and when the two casings are joined together in a closed condition, with the tab terminal passed through and held on the terminal holding portion, the tongue-like spring contact portion of the tab terminal is resiliently contacted with the conductor circuit on the insulating plate.
In this construction, the hood portion of the connector housing and the terminal holding portion are formed integrally with each other, and when the two casings are joined together in a closed condition, with a tab portion of the tab terminal (having the tongue-like spring contact portion) passed through and held on the terminal holding portion, the tongue-like spring contact portion of the tab terminal is resiliently contacted with the conductor circuit on the insulating plate.
In the invention, the insulating plate, having the conductor circuit formed thereon, a wire and a partition plate, disposed between the insulating plate and the wire, are received in the interior of the casing, and the terminal holding portion is formed on the partition plate, and a press-connecting blade is formed at a distal end portion of the tab portion of the tab terminal, and the wire is press-connected to the press-connecting blade, and when the partition plate is fixed relative to the insulating plate, with the tab terminal passed through and held on the terminal holding portion, the tongue-like spring contact portion of the tab terminal is resiliently contacted with the conductor circuit on the insulating plate.
In this construction, the wire is press-connected to the press-connecting blade of the tab terminal passed through and held on the terminal holding portion of the partition plate, and when the partition plate is fixed to the insulating plate, the tongue-like spring contact portion of the tab terminal is resiliently contacted with the conductor circuit on the insulating plate.
In the invention, preferably, the conductor circuit on said insulating plate comprises one of a bus bar and a copper foil.
According to another aspect of the present invention, an electric connection box is provided wherein a flexible printed circuit member, having a pattern circuit of a copper foil formed thereon, is held on a holding plate, and the holding plate, holding the flexible printed circuit member, is received in an internal space formed by a lower casing and an upper casing;
wherein the flexible printed circuit member has a contact portion defined by an exposed portion of the copper foil bent in a direction of a thickness of the holding plate; a recess is formed in the holding plate; a holding groove for holding the contact portion of the flexible printed circuit member is formed in an inner peripheral surface of the recess; a hood portion and a terminal holding portion of a connector housing are formed on the casing facing the flexible printed circuit member; the terminal holding portion has a passage hole, and a tab portion of a tab terminal, having a tongue-like spring contact portion, can pass through and be held by the passage hole; and when the two casings are joined together in a closed condition, the tongue-like spring contact portion of the tab terminal is inserted into the holding groove in the surface of the recess in the holding plate, and is resiliently contacted with the contact portion of the flexible printed circuit member.
In the invention, the contact portion, defined by the bent copper foil portion, is formed on the flexible printed circuit member, and this contact portion is held in the holding groove in the surface of the recess in the holding plate, and the tab portion of the tab terminal is passed through and held by the passage hole in the terminal holding portion of the connector housing. When the two casings are joined together in a closed condition, the tongue-like spring contact portion of the tab terminal is inserted into the holding groove in the holding plate, and is resiliently contacted with the contact portion of the flexible printed circuit member.
In one form of the invention, the hood portion and the terminal holding portion of the connector housing are separate from the casing, and a through hole for passing the hood portion therethrough is formed in the casing, and the connector housing is moved in such a manner that the tongue-like spring contact portion of the tab terminal is inserted into the holding groove in the surface of the recess in the holding plate, and is resiliently contacted with the contact portion of the flexible printed circuit member, and the connector housing is locked to the holding plate, and subsequently the two casings are joined together in a closed condition, so that the hood portion of the connector housing is passed through the through hole.
In the invention, two or more flexible printed circuit members are stacked together, and the contact portions of the flexible printed circuit members are spaced from each other so that the contact portions can be received respectively in the holding grooves in the surface of the recess in the holding plate.